Traveling Crossow Instability for HIFiRE-5 in a Quiet Hypersonic Wind Tunnel (Postprint).

摘要

A scale model of the 2:1 elliptic cone HIFiRE-5 flight vehicle was used to investigate the traveling crossflow instability at Mach 6 in Purdue University's Mach-6 quiet wind tunnel. Traveling crossflow waves were measured with surface-mounted pressure sensors. The crossflow instability phase speed and wave angle were calculated from the cross spectra of three surface-mounted pressure sensors. Both quantities show good agreement with computational values from about 30 to 50 kHz. Repeated runs at the same initial condition show excellent repeatability in traveling crossflow wave properties, and give an estimate of the Experimental uncertainty associated with this technique. Additionally, autobispectral analysis showed the onset and development of moderate nonlinear quadratic phase-locking prior to transition, but not for the peak traveling crossflow wave. The bicoherence achieved only moderate values. No traveling crossflow waves were observed when freestream noise levels were intentionally elevated, but transition occurred for a much lower Reynolds number. It appears that the traveling crossflow instability is not the primary transition mechanism in the noisy flow of Purdue's Mach 6 wind tunnel.